Theorem speiv 1876

Description: Inference from existential specialization, using implicit substitition. (Contributed by NM, 19-Aug-1993.)

Hypotheses

Ref	Expression
speiv.1	|- ( x = y -> ( ph <-> ps ) )
speiv.2	|- ps

Assertion

Ref	Expression
speiv	|- E. x ph

Distinct variable group:   ps, x

Allowed substitution hints:   ph( x, y)   ps( y)

Proof of Theorem speiv

Step	Hyp	Ref	Expression
1		speiv.2	. 2 |- ps
2		speiv.1	. . . 4 |- ( x = y -> ( ph <-> ps ) )
3	2	biimprd 158	. . 3 |- ( x = y -> ( ps -> ph ) )
4	3	spimev 1875	. 2 |- ( ps -> E. x ph )
5	1, 4	ax-mp 5	1 |- E. x ph

Syntax hints:   -> wi 4   <-> wb 105   E.wex 1506

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-5 1461  ax-gen 1463  ax-ie1 1507  ax-ie2 1508  ax-4 1524  ax-17 1540  ax-i9 1544  ax-ial 1548

This theorem depends on definitions:  df-bi 117  df-tru 1367  df-nf 1475

This theorem is referenced by: (None)